Hah, I do this all the time.
If it's a short list of foods in the wrong spot, like one or two items, I just edit the item. (Click on it, and change it from Breakfast to Lunch or whatever, "save" and voila it moves).
If I put an entire meal in the wrong slot (which sometimes is 5 or 10 individual items!), I use the "copy" feature, and copy the entire meal to the proper slot. Then I go to "remove multiple foods" button and erase them out quickly and easily from the "wrong" spot.
Goal 1 - break 200 (46 pounds lost)**DONE**
Goal 2 - leave obesity behind (BMI 29.9, at 185#) **DONE**
Goal 3 - BMI = Normal (154# or less)
| current weight: 172.5